Demand of wireless communication is increasing in terms of easiness of equipment installation, low cost, and easiness of operation. Especially, in an industrial field, there are high expectations for wireless communication that solves a problem associated with the man-hours and cost of cable installation by conventional wired connections and with mobility and easiness to handle.
However, the present situation is such that high requirements specific to industrial applications impede wireless communication from coming into wide use in the industrial field. Therefore, it is required to solve problems proper to wireless communication and ensure reliability equivalent to or more than wired communication.
In this regard, for example, US Patent Application Publication No. 2010/0329137 discloses a method of executing communication, while adapting settings for communication for maintaining high reliability communication by tracking and responding to a change in an wireless communication environment, as a technique for enhancing reliability.
Besides, in ISA 100.11a standards, a method is disclosed that avoids radio interference from other wireless equipment within a system using Time Division Multiple Access (TDMA) and enables communication with a reduced radio interference occurrence rate by executing communication, while randomly changing communication frequencies by frequency hopping every time of sending.